Method and means for the preparation of plaster prior to using



June5, 1928. 1,672,638

L. E. CHASSEVENT METHOD AND MEANS FOR THE PREPARATION OF PLASTER PRIOR TO USING Filed Feb.5, 1927 RTTORNEYS'.

Patented June 5, 1928. I

UNITED STATES PATENT orF-ics.

7 LOUIS EMILE GHASSEVENT, OFv PARIS, FRANCE.

Eamon AND mums roa THE raaraaa'non or rms'i'aa rmoa' To name.

Application fled February 5, 19 37, Serial No.-186,5t82, and in France February 20,1826; v

The present invention relates to improved methods and means for the preparation of a paste of plaster of Paris prior to using.

The fastness with which the plaster of Paris (which will behereinafter more briefly designated by plaster) hardens when mixed with water under ordinary. cond tions causes its use to be somewhat dellcate and ,does not allow. its preparation by on the plaster under preparation, a careful. cleaning of the containers and tools prior,

to said preparation is now indispensable. Further, adding an excess of water when mixing as well as using the plaster when the setting or hardening of the same has already begun result later on-in a considerable reduction of the mechanical resistance of the said plaster. The present invention has for its objects a method which permits, without addition of any other material, to prepare and preserve said plaster for many hours before using it, and a standard apparatus by means of which the invention may be easily put into ractice.

According to the plaster is heated by a water containing material at a temperature comprised between 60 C. and 100C the temperature of the mass bein then prevented from falling below 60 .When mixed with water, the plaster is'kept either in containers the walls of which have a low heat conductibility, or in containers with double walls between which a fluid (for instance water, in liquid or in vaporform at a temperature of from 60 C. to-100 is caused to circulate. In the latter case, the resulting paste may be maintained in the fluid state during many hours (5 and 6 hours andmore when evaporation in the open air is prevented). The plaster mixed and preserved in the manner described is not subject to any alteration or damage. The paste, wliich is used at a temperature above 50 C. begins slowly to become thickerv at about 50 C. and rapidly hardens due to cooling when its temperature falls to about from 38 C. to 45C. according to the fluidity and the chemical composition of the paste employed. A

For instance, a plaster, which has been improved method, the" mixed according to the manner outlined above and in the proportion of 100 grammes for 40 grammes of water, hardens rapidly at 43; a plaster, which has been mixed in the proportion of 100 grammes for grammes of water, hardens rapidly at 38.

The products usually added to the plaster to delay hardening result generally inreducing the speed of hardening. In contradistinction, the plaster prepared according to the present method hardens rapidly as soon I a as the hardening has begun, this facilitating the unmolding. that plaster, when tested after 24 hours as well as after 7 days, are not inferior to those obtained with a plaster which has been mixed under the best conditions of theusual.

method. i

The plaster, so maintained at a temperature above (3., may be preserved in containers and caused to circulate through con- The resistance values of duits in contact with an important quantity either of liquid water steam, atomized wa-. ter or wet materials, without any danger of having the plaster setting Within the apparatus, containers or conduits or at the outlets thereof. Thus the present improved method allows the use of the apparatus commonly employed in the projection of cement to the mechanical application or projection of plaster. The plaster prepared ac'cording to the present method may be applied or projected either under the state of a hot paste or as a powder with atomized water and in no case there will be danger of having some plaster setting in the apparatus and closing the conduits and the outlets thereof.

The present method permits also the setting of the plaster in theapparatus utilized in the fabrication of agglomerates, tiles pantiles, bricks, etc.; the foreign materials which are often added to the plaster do not more need to be .desiccatedowing to the application of the new method-before being mixed with the laster even if the latter is of the fast har ening quality. Thus the present invention permits to obtain rapidly and in greatquantity a veryhomogeneous mixture of water and plaster and forio avoid eign materials, while avoiding to have'the a paratus. heappended drawingshows by way of v to thefipresent methodisets rapidly by coo ing down when cominfi ou't of the .-tion may be ap in a ap aratus. comprises essentially a malaxin vice of any preferred type but provide W1 h doubts wa ls; a temperature comprised betwee 60 C. and 100. C. is maintained in the interval provided between said walls by a circulation of a fluid heated by any preferred means. The plaster, which enters said malaxing device through a loading hopper O, is mixed with water at a tem- Said water, which .is heated by a boiler mav bemeasured in a reci ientE which pjerature comprised between C. and 100 15 D permits to'automatically regu ate the quantitty of mixing water for a given weight of laster.

so o that purpose, said recipient. E comexample a diagrammatic view of an' appa- I Owin to the separate use of heated doustatue making, etc. The plaster aste which is so preserved possesses the a vantage of keeping the same fluidity during the whole duration of its being used.

Obviously, the invention is 'not to 7 any particular embodimentof the general prmclples of the a paratus, since the constructural forms a ove describedand dia-' I26 The plaster which ismixed inAmay be prises 8. P1l111g11l piston F the stroke 0t which may be atgjusted by a pin G and a level tube H- The temperature is observed by means of a thermometer I.

grammatically shown'have only been select.- ed by; way of: example. In particular, the malaxm'g device ma be directly heated by a steam et suppli from theboiler D. and .in'ected within the apparatus.

aving now described my invention, what I claim as new and desire td secure'by Letters Patent is: a

1. A method for the. preparation of a paste of plaster of. Paris which consists in mixmg'the plaster with water, the. mass. havmg a temperature at l t equal to 60C., and preventmg said to peraturedrom lowering below-60 G.'pri r to use.

v2. A, ethod for the preparation of a collected 4 in a recipient J provided with double walls between which is maintained a L temperaturecomprised between 60 C. and

1 C. by a circulation of water'or steam.-

Saidrecipient J may also beseparately employedfor themix ng by han Water at a temperature above 0 C. is added tothe laster in'said recipient. Said plaster ma e then kgpt in said recipient until it is use it Heatin lrectly the mass by steam" reduces wthecoo' ture.

gof the upper layerof the mix- When it is' possible'to utilize all the laster somewhat rapidly (withinhalf an our for instance) after the mixing operation, the heating of the paste containing reci ient may. be avoided by operating as fol ows: The plaster is'inixed with water at a temrature comprised between 90 C. and 100 within a reci ient the walls of which have a lowheat con uctibility in order to avoid 'externalcooling. The plaster mixed under said conditions must be em loyed before its temperature reaches 50 311106 the. mass sets at approximately the latter temperature.

The application of said method allows the mechanical mixinp'; pf many hundred bags of plaster per day under the supervision of a; single operator and to supp y building works with a plaster which is regularly mixed and easy to use. The laster mixed according to the new method 1s not altered or damaged by'the contact of small quanti ties of p aster already hardened so 10 as its temperature remains above 60 C.- hat property enables to considerably reduce the cleaning-which must now be very carefully made-of the tools and recipients devoted to using. or carrying said plaster.

paste of laster of Paris which consists in mixing 7 100 reventing said temperature from lowering ow 60 0. prior to use. 3. A method for the preparation of a paste of laster'of Paris which consists in e plaster with wet materials, the mass aving a temperature between 60 and 100 C. and preventing said temperature from lowering below 60?- G. prior to use 4. A method for the preparation of a paste of lplaster of'Paris which oonsists'in t e plaster -with"water,'- the plaster and water having such a temperature as to bring the mass to a temperature between 60 C. and 100 C. and preventing said temperatune from lowering below 60 C. prior to use. p5. A method for the preparation of a paste of plaster of. Paris which consists in mixing the plaster with water having a temv 6. A method for the preparation of a e plaster. with water, the mass havingJ a teanperature'betWeen I609 C..and

paste of plaster of Paris which consists in mixin the plaster with water and steam, so as to ring the mass to a temperature between 60 C. -and 100 0., and preventing said temperature from lowering below prior to use.

7. A method for, the preparation of a paste of plaster. of Paris which consists in mixing the plaster with water, the mass having a temperature between 60 C. and 100 C. and retarding the natural cooling.

8. A method for the preparation of a paste of plaster of Paris which consists in mixing the plaster with water, 'the mass having a temperature between 60 C. and 100 C. and heating the mass for preventing the natural cooling below 60 C.

9. A method for the preparation of a paste of plaster of Paris which consists in mixing the plaster with water, the mass havinga temperature between 60 C. and 100 C. and heating the mass, by means of a hot fluid. for reventing the natural cooling below 60 .10. A method for the preparation of a paste of plaster of Paris-which consists in 'mixing the plaster with water, the mass having a temperature between 60 C. and 100 C. and heating the mass, by contact with a hot fluid, for preventing the natural cooling below 60 C.

11. A method for the preparation of a paste of plaster of Paris which consists in mixing the plaster with water, the mass having a temperature between 60C. and 100 C. and heating the mass, by means of steam, for reventing the natural cooling below 60 12. A method for the preparation of a paste of laster of Paris which consists in mixing t e plaster with water, the mass heatin the paste. I

having a temperature between 60 C. and 100 and heating the'mass, by means of a circulation of a hot fluid, for preventing the natural coolin below 60C. a

13. In a plant or the. preparation of a paste of plaster of Paris, means adapted to contain t e paste of plaster and means for keeping said paste at a predetermined temperature. 14. In-a plant for the preparation of a paste of laste-r of Paris,"means adapted to contain t e paste of plaster, and means for for the preparation of a 4 15. In a plant paste of plaster of Paris, heat insulated containers for the paste of plaster.

16. In a plant for the reparation of a paste of plaster of Paris, eated containers and heat insulated containers for the paste of plaster.

17. In a plant for the preparation of a paste of plaster of Paris, a container for the paste of plaster having. insulating double walls.

delivering MILE CHASSEVENT. A 

